Gosh Carol, if we tossed our material after 250 usages we'd be dumping a major
part of the collection after each semester. We have a video cleaner/inspection
machine which checks the tapes after each loan and rates them re damage etc. It
works out ok. I toss material that is damaged, outdated or in a dead format. I
certainly don't pay ANY attention to usage for withdrawal ie. if it is being
used, I may toss something if it's NOT being used. Material that is heavily
used may mean that I purchase more than one copy of a particular title. I
worked for 15 years in a medium sized Public Library and did the same thing
there. We wouldn't have the funds to even consider disposing of material just
because it was used a lot. Hope this helps.
elaine